I know that Barrett recently published a recipe for Foul muddamas. I tend to be somewhat of a purist where Foul is concered.
My father was a missionary in Beirut in the 50's when it was still beautiful and safe! He brought back many yummy middle eastern dishes. One of our favorites is this version of foul. Incidentally, when I was living in Egypt, I ate a similar version.
One can of foul beans with their liquid
Juice of 1/2 - 1 lemon (to taste)
minced or crushed garlic (I use 2-3 cloves)
olive oil to taste (approx 1 tablespoon)
Zhater (a mid east melange of spices including sesame seeds, basil, cumin and others) to taste
Dump everything into a pot, heat on the stove until boiling. Serve either in a bowl like soup with toasted pita on the side, or in a pita like a sandwich (this is how you get it from the street vendors in Giza)